1. Technical Field
The present invention relates to an apparatus for the parachute recovery of a payload, and more particularly to a system for autonomously steering an airborne payload to a recovery area and soft landing of the payload.
2. Description of the Related Art
Current parachute recovery systems use an uncontrolled round (or ballistic) parachute. The parachute descends at a vertical speed depending on the relation of the size of the parachute to the weight of the payload. The, recovery systems also have a horizontal speed and direction equal to that of the surface wind. The round parachute system drifts with the wind and impacts the ground at a random orientation. This ground impact usually results in damage to the payload due to the vertical descent rate and the horizontal speed which causes the payload to tumble and/or slam into rocks, trees, etc. In addition, since the round parachute is difficult to steer and drifts with the wind, the ground impact location is random.
Clearly there is a need for a parachute recovery system that can be steered to a precise recovery area and then execute a soft landing, all autonomously.
The related art teaches several parachute recovery systems for the controlled steering of the system to a predetermined recovery area, but none include the soft landing offered by the present invention. For example, U.S. Pat. No. 5,201,482 to Ream, U.S. Pat. No. 5,620,153 to Ginsberg and U.S. Pat. No. 5,899,415 to Conway all use parafoils (or ram air parachutes) for controlling the glide path of the recovery system. These systems all rely on human piloting of the parafoil (i.e.; non-autonomous). U.S. Pat. No. 6,122,572 to Yavnai teaches an autonomous command and control unit for a powered airborne vehicle that uses a programmable decision unit capable of managing and controlling the execution of a mission by using subsystems and a data base capable of holding and manipulating data including pre-stored data and data acquired by and received from the various subsystems. U.S. Pat. No. 6,144,899 to Babb et al. discusses a recoverable airborne winged instrument platform for use in predicting and monitoring weather conditions. The platform is taken aloft by balloon means, accurately determines its present position and uses the data to execute a predetermined flight plan and ultimately guide its descent to a predetermined landing site. This is achieved by installing the instrument package payload in the aerodynamic exterior housing of the recoverable airborne instrument platform.
None of the systems available in the prior include components for autonomously managing and controlling a parafoil recovery system to a pre-selected recovery area, adjusting the orientation of the payload before landing, or executing a landing sequence that includes parafoil canopy flare and stall maneuvers.
A parafoil recovery system capable of autonomously controlling the descent profile of a payload to a predetermined recovery area and manipulating the parafoil to execute a soft landing in the recovery area is provided.
One advantageous feature of the system is a descent profile management system (DPMS) that can determine wind speed and direction, as well as altitude, heading and position of the payload, based on sensor input. The DPMS determines an optimum gliding flight path from the launch point to the desired recovery area, and then controls the recovery system to land the payload at or near the desired recovery site.
Another advantageous feature of the system includes one or more attitude control lines that allow the attitude of the payload to be adjusted either before or during flight to prevent nose-first impact with the ground.
A further feature of the system that offers advantages over known systems includes executing a flare maneuver near the end of the landing sequence by braking the parafoil to slow the descent of the payload for a soft landing. When the payload is within a predetermined height above ground, the canopy of the parafoil is stalled to decrease the ground speed and vertical descent speed at touchdown. The parafoil canopy is released from the payload upon touchdown to prevent the canopy from dragging the payload on the ground after landing. The parafoil recovery system thus delivers a payload at or near a specified recovery location with minimal ground impact damage.
Although the present invention is briefly summarized, the fuller understanding of the invention is obtained by the following drawings, detailed description, and appended claims.